The Ear

The ear is a very sophisticated organ.

Your ear turns sound waves in the air into information in your brain. It can perceive sounds from barely audible to very loud, differentiate their volume and distance, and pinpoint the direction of a sound source with an amazing degree of accuracy. The short video on this page demonstrates in greater detail how your ear hears.

Ear Graphic

The outer ear.

The outer ear consists of the visible part (also called the auricle or pinna) and the ear canal. Sound waves are transmitted through the air, collected, and guided through the ear canal to the tympanic membrane (eardrum). The eardrum is a flexible, circular membrane that vibrates when struck by sound waves.

The middle ear.

The middle ear is an air-filled space separated from the outer ear by the eardrum. The middle ear contains three tiny, important bones — the malleus, incus, and stapes (often referred to as the hammer, anvil, and stirrup) and collectively known as the ossicles. These form a bridge from the eardrum to the inner ear. The ossicles also vibrate in response to movements of the eardrum, and in doing so amplify and relay sound to the inner ear via the oval window.

The inner ear.

The cochlea, or inner ear, is similar in shape to a snail shell. It contains several membranous sections filled with fluids. When the ossicles conduct sound to the oval window, the fluid begins to move. This stimulates the tiny hearing nerves (hair cells) inside the cochlea, which then send electrical impulses via the auditory nerve to the brain, where they will be interpreted as sound.

This animated video demonstrates how the human ear works.